Methods of activating enzyme breakers

Abstract

A method of treating a subterranean formation, the method including placing a well treatment fluid comprised of at least an enzyme and a breaker additive in the subterranean formation. Initially, the pH of the well treatment fluid is about 11.5. The breaker additive reduces the pH of the well treatment fluid by at least 1.5 to increase the activity of enzyme and accelerate hydrolysis of a crosslinkable component.

What is claimed is: 
     
       1. A method of treating a subterranean formation, the method comprising
 placing a well treatment fluid comprised of a crosslinkable component, an enzyme, and a breaker additive in the subterranean formation, the well treatment fluid having an initial pH from about 11 to about 12, wherein the crosslinkable component comprises a first viscosity while the well treatment fluid is placed in the subterranean formation, 
 wherein the breaker additive reduces the pH of the well treatment fluid by about 2.0 to about 3.0 pH units resulting in a pH of about 8 to about 10 for the well treatment fluid after the well treatment fluid is placed in the subterranean formation in order to increase an activity of the enzyme and accelerate hydrolysis of the crosslinkable component, and wherein the crosslinkable component comprises a second viscosity higher than the first viscosity after the well treatment fluid is placed in the subterranean formation. 
 
     
     
       2. The method of  claim 1 , wherein the breaker additive is a polymeric fiber. 
     
     
       3. The method of  claim 1 , wherein the breaker additive is an acid encapsulated with an encapsulating material. 
     
     
       4. The method of  claim 1 , wherein the breaker additive is an ester. 
     
     
       5. The method of  claim 4 , wherein the ester is encapsulated with an encapsulating material. 
     
     
       6. The method of  claim 1 , wherein the well treatment fluid comprises an initial viscosity from about 1 cP to about 100 cP. 
     
     
       7. The method of  claim 1 , wherein the breaker additive degrades when the well treatment fluid is in the subterranean formation to cause the well treatment fluid to have a third viscosity that is lower by at least one order of magnitude than the second viscosity. 
     
     
       8. A method of treating a subterranean formation, the method comprising
 placing a well treatment fluid comprised of at least an enzyme and a breaker additive in the subterranean formation, the well treatment fluid having an initial pH from about 11 to about 12, 
 wherein the breaker additive reduces the pH of the well treatment fluid by about 2.0 to about 3.0 pH units after the well treatment fluid is placed in the subterranean formation, resulting in a pH of about 8 to about 10 for the well treatment fluid in order to increase the activity of the enzyme and accelerate hydrolysis of a crosslinkable component of the well treatment fluid, and wherein the breaker additive comprises an encapsulating material configured to melt when a surrounding temperature exceeds a threshold temperature. 
 
     
     
       9. The method of  claim 8 , wherein the breaker additive comprises a polymeric fiber. 
     
     
       10. The method of  claim 8 , wherein the breaker additive comprises an acid encapsulated with the encapsulating material. 
     
     
       11. The method of  claim 8 , wherein the breaker additive comprises an ester. 
     
     
       12. The method of  claim 11 , wherein the ester is encapsulated with the encapsulating material. 
     
     
       13. The method of  claim 8 , wherein the crosslinkable component comprises at least one of a copolymer of 2-acrylamido-2-methyl-propane sulfonic acid and acrylamide; a terpolymer containing monomers of 2-acrylamido-2-methyl-propane sulfonic acid, acrylic acid, acrylamide, vinyl pyrollidone; or derivatives thereof. 
     
     
       14. The method of  claim 8 , wherein the breaker additive comprises a chemical that reduces the initial pH of the well treatment fluid after the surrounding temperature of the well treatment fluid exceeds the threshold temperature. 
     
     
       15. The method of  claim 8 , wherein the breaker additive reduces a viscosity of the well treatment fluid by at least one order of magnitude. 
     
     
       16. The method of  claim 8 , wherein the enzyme is initially in an inactive state due to at least the solution pH and temperature. 
     
     
       17. The method of  claim 1 , wherein the enzyme is not encapsulated.